Filarial selenium glutathione peroxidase: a probable immunodiagnostic marker for lymphatic filariasis

Lymphatic filariasis (LF) caused by Wuchereria bancrofti is widely prevalent in tropical and subtropical countries. Night blood film examination is most commonly used for diagnosis of filariasis but is cumbersome and labour intensive. In order to develop an indirect ELISA-based immunodiagnostic test, the importance of antifilarial IgG subclasses was evaluated in bancroftian filariasis patients. Blood samples from healthy individuals and different categories of LF patients were used to estimate the diagnostic potential of selenium glutathione peroxidase antigen purified from the bovine filarial parasite Setaria cervi. This antigen reacted with both IgG1 and IgG4; however, the IgG1 response was greater in microfilaraemic patients and the IgG4 response was higher in chronic filarial patients. The diagnostic sensitivity of IgG1 and IgG4 was 97% and 96% whereas specificity was determined to be 95% and 98% respectively. Our observations suggest that SeGSHPx could be an alternative diagnostic marker for the detection of bancroftian filariasis in an endemic area.